1. Field of the Invention
This invention relates to air compressors otherwise known as turbochargers and superchargers for forcing air into the air intake of an internal combustion engine. More particularly, this invention relates to a compressor of this type which is independently powered by a turbine engine. This invention has particular application for automobiles, but is not limited thereto, and may be used in other applications.
2. State of the Art
It is well known in the art of internal combustion engines to provide an air compressor at the air intake of the engine so that air entering the intake is first compressed and the power output of the engine is thereby increased. These air compressors are typically engaged only temporarily when it is desirable to boost the engine""s output, for example when accelerating an automobile. There are two basic types of air compressors: turbochargers and superchargers.
Turbochargers are powered by the exhaust gases of an engine. They generally include a turbine and a compressor which are coupled to each other by a shaft. The turbine is driven by the exhaust gases of the engine. The rotation of the turbine causes the compressor to rotate. The compressor compresses air entering the intake manifold of the internal combustion engine.
Superchargers include a compressor which is gear driven or belt driven by a rotating shaft of the internal combustion engine. The rotation of the compressor compresses air entering the intake manifold of the internal combustion engine.
Both turbochargers and superchargers achieve the same purpose. They both boost the air pressure in the intake manifold of the internal combustion engine. This results in an increase in the power output of the engine. However, both turbochargers and superchargers have disadvantages.
One of the disadvantages of turbochargers is referred to as xe2x80x9cturbo lagxe2x80x9d. When the turbo charger is engaged, it takes four to five seconds before sufficient exhaust pressure is built up to spin the turbine blades fast enough to provide a power boost. Another disadvantage of turbochargers is that they can interfere with the engine""s exhaust system. This has an adverse effect on the engine""s performance.
Superchargers do not have the lag experienced by turbochargers. However, they require a substantial amount of engine horsepower to be driven. Where turbochargers and superchargers derive power from the engine, they also require relatively complex couplings to the engine.
In order to avoid taxing the engine with the supercharger, it is known to provide an independently powered supercharger for compressing air. These independently powered superchargers have taken the form of a conventional piston engine, a rotary engine, an electric motor, and a hydraulic motor, and are described in, e.g., U.S. Pat. No. 2,165,360 to Elliott, U.S. Pat. No. 4,610,235 to Grunig, U.S. Pat. No. 5,456,240 to Kanesaka, and U.S. Pat. No. 5,577,385 to Kapich, all of which are hereby incorporated by reference herein in their entireties.
Typically, for most commercial vehicles, the horsepower (HP) required to operate a supercharger compressor varies from 40HP-150HP (at 90,000 to 140,000 rotations per minute (RPM)). In order to produce 40HP-150HP at 90,000 to 140,000 RPM from an independent engine, using the systems of the prior art, a relatively large independent engine with a complex gear mechanism is required. For example, a conventional piston engine or rotary engine capable of producing the desired horsepower and RPM will weigh well in excess of one hundred pounds. Similarly, an electric motor engine which produces the required horsepower and RPM will typically weigh between 100 and 500 pounds and will require a substantial power source to operate. A hydraulic motor will require a large pump and will have difficulty producing the high RPM required. In all cases, the independent supercharger of the prior art adds considerable weight to the system, and requires a substantial area (typically a minimum of 4 cubic feet) for installation. Thus, these independently powered supercharger systems have not found wide-spread utilization in the auto industry.
It is therefore an object of the invention to provide an air compressor for charging an internal combustion engine.
It is also an object of the invention to provide an air compressor for charging an internal combustion engine which does not draw power from the engine.
It is another object of the invention to provide an air compressor for charging an internal combustion engine which does not have a lag time when engaged.
It is a further object of the invention to provide an air compressor for charging an internal combustion engine which does not restrict the exhaust system of the engine.
Another object of the invention is to provide an air compressor for charging an internal combustion engine which is simple to install, which is light in weight, and which does not require substantial area for installation.
In accord with these objects which will be discussed in detail below, the air compressor of the present invention includes a first turbine (also referred to as xe2x80x9cthe compressorxe2x80x9d) for blowing compressed air into the intake manifold of an internal combustion engine and a second, fuel powered, turbine (also referred to as xe2x80x9cthe turbinexe2x80x9d) for driving the compressor. According to a first embodiment, the exhaust from a small gas powered turbine is coupled to the driving turbine of a standard turbocharger. The turbocharger operates in a normal manner except that it can operate at a constant boost, does not use engine horsepower, is easier to install, and does not interfere with engine exhaust. According to a second embodiment, the drive shaft of a small gas powered turbine is coupled to the drive shaft of a standard supercharger or turbocharger compressor. The supercharger operates in a normal manner except that it can operate at a constant boost, does not use engine horsepower, is easier to install, and does not need to be coupled to a rotating shaft of the engine. According to a third embodiment, a small gas powered turbine drives a compressor which supplies compressed air to the intake manifold of the engine being charged as well as supplying compressed air to the combustion chamber of the small gas powered turbine. The gas powered turbine rotates the compressor to drive it and provides compressed air to both the intake manifold of the internal combustion engine and to the combustion chamber of the small gas turbine. The compressed air outlet of the compressor can provide a constant boost, does not use engine horsepower, is easy to install, and does not need to be coupled to a rotating shaft or the exhaust system of the engine.
According to the invention, the gas powered turbine may be single stage or multi-stage. Both the gas powered turbine and the compressor can be axial flow, radial flow, centrifugal, or any combination thereof. Various types of combustors can be utilized including annular and can annular combustors. The combustor may be positioned between the compressor and turbine, at a remote location, or may be arranged in a standard reverse-flow arrangement. The essence of the invention is to provide a self-powered turbine for driving the compressor. As used herein, self-powered means that the turbine does not derive power from the internal combustion engine into the intake manifold of which it is blowing compressed air.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.